tcp: better TCP_SKB_CB layout to reduce cache line misses

[cascardo/linux.git] / net / ipv6 / tcp_ipv6.c

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 9400b43..132bac1 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1412,6 +1412,13 @@ static int tcp_v6_rcv(struct sk_buff *skb)
 
        th = tcp_hdr(skb);
        hdr = ipv6_hdr(skb);
+       /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
+        * barrier() makes sure compiler wont play fool^Waliasing games.
+        */
+       memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
+               sizeof(struct inet6_skb_parm));
+       barrier();
+
        TCP_SKB_CB(skb)->seq = ntohl(th->seq);
        TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
                                    skb->len - th->doff*4);